In a small skillet add enough oil to fill the bottom of the skillet about a half inch. Place the skillet over medium-high heat and allow the oil to heat for 10 to 12 minutes.

When the oil is hot carefully place one corn tortilla in the hot oil. Let it cook for about 30 seconds on the first side. Using tongs or two forks flip the tortilla over. Once both sides are cooked crisp let the tortillas drain on paper towels to soak up the extra grease. Keep in a warm oven until ready to serve.

To serve spread hot refried or black beans on one tostada shell and sprinkle with a layer of shredded cheese. Warm the cheese (in a warm oven) until the cheese is melted. If your beans were hot enough to melt the cheese in the first place you can skip the melting step.

Add another tostada shell on top of the melted cheese. Add a layer of steak Carnitas meat and then top with your favorite toppings. Eat right away so that the shells don't get soggy.